Frequency changer for short waves



Jan. 21, 1930. s s ET AL 1,744,668

- FREQUENCY CHANGER FOR SHORT WAVES Filed Aug. 14, 1925 INVENTOR MENDEL oswos BY RICH? KUMMICH Patented Jan. 21, 1930 UNITED STATES PATENT OFFICE MENDEL OSNOS AND RICHARD KfIMMIGI-I, 0F BERLIN, GERMANY, ASSIGNORS TO GESELLSCHAFT FUR DRAHTLOSE TELEGRAPHIE M. B. I-L, OF BERLIN, GERMANY,

A CORPORATION OF GERMANY I FREQUENCY CHANGER FOR SHORT WAVES Application filed August 14, 1925, Serial No. 50,165, and in Germany August 16, 1924.

Our invention relates broadly to devices which are used in the art of electricity for changing electric energy of one frequency into electric energy of another frequency.

5 More particularly our invention relates to a device of this kind commonly called a static frequency changer because all parts thereof are stationary. A static frequency changer, as is well known in the art, consist-s generally of a core of magnetic material usually of iron or some alloy thereof and a winding surrounding said core.' A primary circuit is connected to the source of fundamental frequency and to said winding while, similarly, a secondary circuit is connected to the work circuit of the new frequency and to said winding. Sometimes the primary circuit and second circuit utilize the same winding on the changer and othertimes they are connected to separate windings.

An object of the invention is to provide a frequency changer of the above kind which is adapted for use with very short wave lengths and which is constructed to dissipate the large amounts of heat which is inherently generated in very high frequency apparatus.

Other objects will be apparent from the following description and claims when considered with the accompanying drawing, in which Fig. 1 shows a frequency changer according to the invention with primary and secondary circuits connected thereto, the primary and secondary circuits utilizing the same winding;

Fig. 1- shows a frequency changer according to our invention which is arranged to take up but a small space;

Fig. 2 shows a modified form of frequency changer according to the invention having a single winding; and

Fig. 3 shows a frequency changer similar to that of Fig. 2 but having both a primary and secondary winding.

The use of iron or other magnetic material for static frequency changers for the purpose of producing very short waves meets with a difiiculty residing in the fact that very high losses occur. Reasons for these high losses are (1) because a high number of ampere turns per centimeter is required for asmall amount of iron, thereby providing high magnetization, and (2) because the frequency is very high. The consequence is very marked heating of the transformer or changer. it being impossible to carry off the heat thus generated by ordinary means.

' Now, conformahly with the present invention the transformer is so designed that the iron presents a large radiating surface compared to its volume, so that marked local heating is avoided. According to the invention, a conductor which is supplied with the current of fundamental frequency, is surrounded by a thin layer of ferro-magnetic material, the thickness of said layer preferably not exceeding one-tenth of one millimeter. By the term thin layer we mean a layer of ferromagnetic material of such a thickness that it will be saturated at a point between the minimum and maximum value of the'current flowing in the conductor, and it is this meaning that is to be given to the term as used throughout the hereinafter appended claims. This surrounding of the conductor with the layer of ferromagnetic material can be accomplished in various ways, described hereinafter more in'detail.

Referring to Fig. 1, a wire D possessing good conducting qualities, or a stranded wire adapted for high frequency current. can be wrapped with thin ferro-magnetic capillary wire 1. To the conductor D having a braiding of iron wire there is connected the secondary circuit S, which may be tuned to the desired higher frequency by the condenser 2. The primary circuit P whichmay-consist of simply a source 3 of fundamental frequency is also connect-ed to the conductor D.

Instead of braiding the conductor wit-h capillary wire 1, the iron can be placed qpon the conductor in the form of a thin coat in any well known manner, as for instance, by means of a galvanizing, disintegration, or electrolytic process. In order to safeguard againstoxidation, it is a good plan to provide over the transformer a covering of chromium or an amalgam, or a similar means.

If the longitudinal dimension of'a single wire, as shown in Fig. 1, should be too grea it is recommendable to wind the wire bifilar fashion, or to bend it zigzag-fashion, as indicated in Fig. 1

Referring now to Figs. 2 and 3, in this form of carrying the idea into practice the magnetic material is not placed upon the conductor D directly, but upon hollow bodies I and II, most preferably porcelain tubes. The conductor or conductors'to which the primary or the secondary circuitsP and S are connected are introduced into the hollow bodies.

In Fig. 2 wherein the frequency changer is provided with but a single winding, its terminals are denoted by K and K In Fig. 3 wherein the frequency changer is provided with two windings, the terminals of the pri- H mary winding are denoted by K and K while the terminals of the secondary winding are denoted by K and K 7 Having described our invention, we are entitled to all modifications thereof as fall fairly within its spirit and scope, as defined by the following claims:

'1. A frequency changer for short Waves comprlsmg, an electric conductor and a thln layer of magnetlc materlal surrounding sa1d conductor.

ranged bifilar fa'shion, and a thin layer of magnetic material surrounding said winding. 5. In a frequency changer, an electrical conductor, and a layer of magnetic material whose thickness is no greater than one-tenth ofa millimeter surrounding said conductor. 6. In a frequency changer,- a conductor 1 having a core of low resistance material and an outer shell of high permeability.

7 Ina frequency changer a conductor having a core of non-magnetic conducting material and an outer shell of magnetic material. I 8. In a frequency changer, a conductor of low internahelectricalimpedance and high outer magnetic permeability.

9. In a frequency changer, a conductor connected to a source of energy, and a magnetic material surrounding said conductor.

10. In a frequency changer, a conductor provided with a coating of magnetic material;

said material being adapted to readily dissipate l'ieat.

11. In a frequency changer, an iron clad conductor and a coating adapted to prevent oxidation of said iron surrounding said eonductor.

' 12. In a frequency changer a conductor provided with a copper core, a ferro-magnetic coating on said core,.and a non-oxidizing coating upon said ferro-magnctic substance.

MENDEL OSNOS. RICHARD KUMMIGH. 

